Rapid advances in Xanthomonas-derived transcription activator-like (TAL) effector technology have enabled any researcher to construct tools for targeted alteration of gene sequence or expression. Highly conserved 33-35 amino acid TAL effector repeat domains each bind to one nucleotide of DNA with specificity dictated by the identities of two hypervariable residues.1 To construct a protein capable of recognizing a specific DNA sequence, repeats with different specificities are simply joined together into a multimerized array. Much recent effort has focused on engineered TAL effector nucleases (TALENs), fusions consisting of TAL effector repeat arrays and a nuclease domain that enable routine targeted modification of endogenous genes in a variety of different organisms and cell types. TAL effector repeat arrays have also been fused to transcriptional activation domains to construct artificial TAL effector activators (TALE-activators) that can increase endogenous gene expression in plant and human cells.2-10 Artificial transcription factors that can be custom-made for target genes of interest have already shown promise as broadly useful research tools and may have potential for therapeutic applications.11 